Month: July 2013

Links: How To Set Up A Wireless Hotspot (Access Point Mode) That Supports Android In Ubuntu

A wireless hotspot enables a computer to serve as a router over Wi-Fi. Ubuntu lets you easily create a wireless hotspot by using the Network Manager, but it uses an ad hoc network and most Android and Windows Phone devices can’t connect to such networks.
For this reason, I’ve created (in collaboration with Satya) a script called AP-Hotspot that automatically creates an infrastructure (Access Point mode) wireless hotspot in Ubuntu that should work with Android and Windows Phone devices. The script uses hostapd and dnsmasq and it requires Access Point mode support for your wireless card – AP-Hotspot checks for this automatically and won’t run if your wireless card doesn’t support it.

Full article:
How To Set Up A Wireless Hotspot (Access Point Mode) That Supports Android In Ubuntu (Linux A.I)
Alternate location of above article (WebUpd8)

If you don’t feel comfortable running a script, the script is based on these instructions, so if you want you can do it manually:

[GUIDE] Making infrastructure wifi hotspot on ubuntu 12.04/12.10 (xda developers)

Link: Chromecast: Exploiting the Newest Device By Google

Chromecast-stockOn Wednesday, July 24th Google launched the Chromecast. As soon as the source code hit we began our audit. Within a short period of time we had multiple items to look at for when our devices arrived. Then we received our Chromecasts the following day and were able to confirm that one of the bugs existed in the build Chromecast shipped with. From that point on we began building what you are now seeing as our public release package.

Exploit Package:
Our Chromecast exploit package will modify the system to spawn a root shell on port 23. This will allow researchers to better investigate the environment as well as give developers a chance to build and test software on their Chromecasts. For the normal user this release will probably be of no use, for the rest of the community this is just the first step in opening up what has just been a mysterious stick up to this point. We hope that following this release the community will have the tools they need to improve on the shortfalls of this device and make better use of the hardware.

Full story here:
Chromecast: Exploiting the Newest Device By Google. (GTVHacker)

Additional comment: These devices might be a lot more useful to some of us if someone could figure out how to 1) Add a wired network connection, 2) Add an optical audio output for those of us with older receivers (that don’t have HDMI connections) and TVs (that don’t pass audio from a HDMI port back to the receiver). They’re obviously selling these to the low-income crowd, so why would they not assume that you might want to connect this to perfectly good but slightly dated equipment that requires optical audio, or maybe even to a large screen computer monitor that doesn’t have any audio capabilities?

Additional additional comment: If the XBMC developers could create an add-on that would emulate the Chromecast device and in effect turn XBMC into a Chromecast receiver WITHOUT the need for the Chromecast dongle, that would make us VERY happy!

 

Link: How to Add USB Storage to the Raspberry Pi

You will find that in order to add, store and remove data to a Raspberry Pi, you have three main options:

  • SD/SDHC card
  • USB flash drive
  • USB hard disk drive

You can also use network drives, USB DVD-R drives and NAS devices (perhaps powered by a Raspberry Pi!) for additional storage, but those listed above should be considered your three primary options.

We’ll take a look at the three options in more detail, how they can be used most effectively and at any shortcomings or drawbacks.

How to Add USB Storage to the Raspberry Pi (MakeUseOf)

Link: How to Move Your Home Folder to Another Partition [Linux/Ubuntu]

If you have accepted the default option while installing Ubuntu, or that your computer comes with Ubuntu pre-installed, chances are that your Home folder and the system folders all lie in the same partition. This is perfectly fine, but if you want to upgrade your existing Ubuntu version, or reinstall Ubuntu, you won’t be able to preserve your app settings, or even retain your files and documents. One of the good practice is to give the Home folder its own partition, so whatever changes you made to the System folder won’t affect your Home directory, and you can easily upgrade or reinstall Ubuntu with ease.

If you want to move your Home folder to another partition, here is how you can do so.

How to Move Your Home Folder to Another Partition [Linux/Ubuntu] (Make Tech Easier)

Link: How to convert from .deb to .rpm and viceversa

deb is the extension of the Debian software package format and the most often used name for such binary packages. Debian packages are standard Unix ar archives that include two gzipped, bzipped or lzmaed tar archives: one that holds the control information and another that contains the data. The accepted program for handling these packages is dpkg, commonly used via other programs such as apt/aptitude or Gdebi.

RPM Package Manager (RPM) is a package management system. The name RPM variously refers to the .rpm file format, files in this format, software packaged in such files, and the package manager itself. RPM was intended primarily for GNU/Linux distributions; the file format is the baseline package format of the Linux Standard Base.

If you can only find some software you want to install in one of these package types but you need the other, this article tells you what to do. Note we are just passing along the link, and do not guarantee that this will work:

How to convert from .deb to .rpm and viceversa (Linuxaria)

Powering a Nexus 7 tablet through the USB port while simultaneously connecting a USB device

The links in this article are for informational purposes only. Please read the final paragraph of this article before you actually do anything based on these links.

If you have ever tried to connect a Nexus 7 tablet to an external USB device, such as a USB memory stick or a wired network adapter, you know that you need a special “OTG” cable and that the tablet will power the device. While you can purchase various kind of “OTG” Y-cables, which purportedly will allow you to use an external device (or even connect to a USB hub so you can use multiple devices) while at the same time allowing a charger/power supply to be connected, this doesn’t work with a stock Nexus 7. At best you can send power to the connected device, reducing the drain on the battery in the Nexus 7, but you cannot send power back into the Nexus 7 simultaneously, even though you can charge the Nexus 7 while you are using it if the charger is the only thing you have connected.

There is a way around this but it involves “rooting” the device. If you don’t know what “rooting” a device means, or the implications of it, you’ve come to the wrong place because we’ve never done it – the mere thought of turning our Nexus 7 into an expensive brick is enough to dissuade us from trying it. However, in the course of trying to research this, we came you with links that might be useful to Nexus 7 owners that are braver (or maybe bigger gamblers) than we are.

The key to this is “Timur’s Kernel” – if you remember nothing else from this article, remember “Timur’s Kernel”. As we searched for information on this, time and again, we were sent back to this message thread:

Timur’s Kernel – USB ROM – USB Host Power Management – USB Audio (RootzWiki)

SOMEWHERE in that thread, which as of today is 358 pages long and still growing, is the information you need. Actually, the meat of it is in the very first post on page 1, with additional explanation on page 7. If you don’t feel like wading through all of that (seriously, who reads a thread that long?), the following page pretty well summarizes what you need to know. Just keep in mind that you probably don’t have to make your own cable if you don’t want to; there is almost certainly a cable available at eBay or Amazon that would serve the purpose, although you might need to search that long thread to figure out which one(s) will work:

USB host mode power management extension for Nexus 7 (mehrvarz.github.io)

Oh, and if you have ever wondered why you need a special “OTG” cable to connect an external device, it’s because pins 4 and 5 must be shorted together at the micro USB connector — some folks have made their own (also see here), though we DO NOT recommend that because they are fairly inexpensive to purchase, and if you do it wrong you could damage your device. On some other devices, you can use a particular value resistor (which varies depending on the model) instead of a direct short, and that indicates that the device should both send data and allow charging simultaneously, but that doesn’t work with a Nexus 7. That’s why you need “Timur’s Kernel” — as we understand it, it basically bypasses the (non-existent in the Nexus 7) circuitry that detects the resistor, and acts as if the resistor were present, thereby allowing the Nexus 7 USB port to be used for charging and transferring data simultaneously.

We are not recommending you do this, nor are we attempting to discourage you, but if you don’t understand the implications of rooting your device then we suggest you don’t do this until you have read up on the subject of rooting an Android device, and fully understand and accept the risks of rooting. And if you decide to proceed, do so at your own risk, realizing that there is a very real chance you could turn your Nexus 7 into an expensive paperweight. If that should happen, don’t come crying to us, because we warned you!

If you actually do this and get it to work, please feel free to post a comment. If possible, please mention which cables or Y-adapters, etc. you used. Also, if you find any other particularly informative pages in that much too long thread, please feel free to post the links and mention why they are significant.

Links: Alternative ways to power a Raspberry Pi

Sorry this is not a complete article, just a few links of interest for those who might be looking to provide power to a Raspberry Pi using alternative methods. We may add to this list later on if we find any more good resources on the subject.

How do I supply power through the GPIO? (Raspberry Pi Stack Exchange) — note that the short answer is, “you shouldn’t”, but the discussion is worth reading.

Troubleshooting power problems (from the R-Pi Troubleshooting page at elinux.org) — more information about how the Raspberry Pi is powered.

RPi 5V PSU construction (elinux.org) — for those that might want to build their own.

Running The Raspberry Pi On Batteries (Dave Akerman) — includes several tips for cutting power consumption.

Raspberry PI UPS (jkliemann.de) – an uninterrupted power supply for a Raspberry Pi.

Not such a great deal on a VoIP PBX?

Is this the worst deal ever on a VoIP PBX? Probably not, but in our opinion it’s certainly not the best deal by a long shot, unless maybe they are providing a GREAT support package. See this thread on the PBX in a Flash forum. Interesting that their ad says “All products are sold on a No Return Basis.”

In case you’re not quite getting the picture, we’ll point you to this totally unrelated article. 😉 Compare what you see there with what’s pictured in the ad at the above link. We cannot know for sure that the innards of that ~$350 PBX are actually a ~$35 Raspberry Pi, at least not unless someone purchases one and disassembles it to find out, but you can definitely spot some similarities in the placement of the various input/output ports.

Rather than purchase any device costing a few hundred dollars on a “No Return Basis”, you might want to consider just getting a Raspberry Pi and using one of the distributions mentioned in our article, Asterisk on a Raspberry Pi – which distribution is best?. Even if you don’t agree with our conclusions in that article, any of the distributions mentioned there would probably be a better choice in the long run. But, that is just our opinion.

Link: The Ten Minute Guide to diff and patch

This is a quick guide to diff and patch which will help you in these situations by describing the tools as they are most commonly used. It tells you enough to get started right away. Later, you can learn the ins and outs of diff and patch at your leisure, using the man pages.

The Ten Minute Guide to diff and patch (stephenjungels.com)

Link: How to build a cross compiler for your Raspberry Pi

A cross compiler is a compiler that runs on one platform/architecture but generates binaries for another platform/architecture. With devices like the Raspberry Pi, where you really don’t have much CPU or memory to work with, if you’re doing any heavy compiling (like when working on the kernel) a cross compiler is the only way to go. For example, I build all my Raspberry Pi kernels on my nice Sandy Bridge Xeon E3 home server where they compile in only a fraction of the time they would on the Pi.

How to build a cross compiler for your Raspberry Pi (Chris’s Digital Realm)